A photosensitive body is used in an electro-photographic type image forming device such as a copying machine, printer, and facsimile, and includes a cylindrical electrically conductive drum body formed with a photosensitive layer at its outer peripheral surface, an electrically conductive shaft rotatably supporting the photosensitive body, and an electrically conductive contact member for electrically connecting the photosensitive body to the shaft by a sliding contact between the contact member and the shaft.
A conventional photosensitive body installed in a process cartridge detachable relative to a main frame of the image forming device is generally in a form of a cylindrical shape having a small diameter. The drum body includes an aluminum tube whose outer surface is formed with a photosensitive layer. Further, an end flange is fitted at each end of the aluminum tube. The shaft extends through a radial center of each flange. One of the flanges is provided with a gear for drivingly rotating the photosensitive body about its axis.
In such conventional photosensitive body, the end flange is made from a synthetic resin in view of reduction in weight and cost. Here, in the electro-photographic process, the drum body must be electrically connected to the main frame because of the necessity of grounding. To this effect, a contact member such as an electrically conductive plate (grounding plate) is provided for electrical connection between the shaft and the drum body.
More specifically, the electrically conductive plate has generally disk shape and is forth-fitted with inner peripheral side of each end portion of the drum body along with the end flange. The electrically conductive disk plate has an outer peripheral portion provided with a protrusion adapted to be in contact with the drum body, and has a radially center portion formed with a through-hole through which the shaft extends. The electrically conductive disk plate has a reed like contact portion that is in resilient contact with an outer peripheral surface of the shaft extending through the through-hole. Such conventional arrangement is described in laid open Japanese Patent Application Publication No. H10-207291, 2002-91234, 2004-102270, and 2006-72039.